Clutch and gearing control



Nov. 7,1-944.` E. AjTHoMPsoN 5 I 2,362,418

CLUTCHAND GEARING CONTROL` y l original 'Filed March 15, 1957 7sheetsshawl www Nov. 7, 1944. E. THOMPSON CLUTCH AND GEARING CONTROLOriginal AFiled4 March l5, 1957 Sheets-Sheet?.

Ath rug:

Nov. v7, 1944. E. A. THQMPsoN CLUTCH AND GEARJENG CONTROL original FiidMrch 15, 19:57l 7 sheets-sheet s E.' A.` 'rHoMPsoN 42,362,418 CLUTCH ANDGEARING CONTROL y Nov.v '.7,

original Filed IImran 15,1193?v 7 sheetseshet 4 Nov: 7, 1944. E, A,THOMPSON 2,362.418

CLUTCH-AND GEARING CONTROL Original Filed March lA5, 1957 7 SheetsSheet5 V r M K Q@ "mit NWN?, E. E. A. THoMPsc-JN I 2,362,413

CLUTCH AND GMRING CONTROL Original Filed March 15, 1937r{Sheeizs-She'el: 6

liVeN-tor Nov. 7, w44; E. A. THOMPSON 23329438 y CLUTCH AND GEARINGCONTROL Original Filed March l5.,- 1957 7 Sheets-Sheet 7 Earl A.ThompsomfBloomi-leld Hills, Mich., as-

signor to General Motors Corporation, Detroit, Mich., a. corporation ofDelaware original application March 15. isaaseriai no. 130,956. Dividedand this application February 14, 1940, SerialNo. 318,945 v 24 Claims.(m. 192.01)

' The invention of the present application is related to andassociatedwith my prior U. S. Serial Number 659,752, tiled March s,1933, to U. s.v Serial Number', 747,386, filed October 8, 1934, nowmaturedA as -U. S. 2,195,605, and to my U. S. Serial Number 45,184,filed October 16, 1935, now ma tured as U. S. 2,193,304. The presentapplication is a divisional of my S. N. 130,956, filed March 15, 1937,now matured as U. S. 2,193,524. In the first of these I show anAautomatically con-l trolled gearing unit' combined with a standardtiple units.4 An lexample oi.' this is in seriatim two-speed gearingdesigned to provide four forward speeds-as' described in my S. N. 45,184in particular.' .In such-an assembly, .flrst will be low gear in both'units;l secondf Twill be through .low in- -one'unit with the otherindirect drive;

.third willbe by direct drive in the rst unit,

` with low in the'second. "High'will -be direct gearshift, providingautomatic ,changes over a range of hand selected speed ratiosl mastercontrol by operator-operable members,

yielding a high degree of safety in practical use.

L .In the third application I show further improvements-which 'provideadded safety features for operator domination over the normallyautomatically shifted ratio regime, useful during a wider range ofoperating conditions than. in the preceding disclosures. f'

A major improvement in the present divisional application 'is theoperator-operated means by whichI obtain not only a controlled clutch'rate control, but also .provide additional compensated rate control inone unit -according to the ratio in which the other unit is driving.This feature adds smoothness to the overall operation not believedavailable in prior art'. mechanisms of this character. Y.

' Further improvement in servo means so are' ranged as to tend towardnon-failure is shown in my double pump drive, described further indetail.

An additional feature of value is the means whereby the oildrainingffrom the direct coupling clutch plates is accomplished duringengagement, and the further means by which thel c Aoil film therein isbroken at disengagement, with a minimum of drag effect which otherwisewould cause encessivewear. v,

.Of ,outstanding novelty is the means whereby I obain automatic shift'inboth forward drivingunits of my assembly 4by sequentially combining thepressure rise characteristics of the servo pump with the furthercharacteristics-of governor and operator-operable accelerator pedal po-I fsition, wherein a full range of forward driving "soeedratios is madeavailable',` depending upon .the settings 7of the manual controlmeans,.otherv than the aforesaid pedal. f

' As I have demonstrated, controls for transmise.

: sion unitsconnected in multiple'series between t 'ie power' and theload for obtaininga full range' of transmission ratios require a regimewherein l during a cyclic shift from lowest ,ratio` to highest .ratio orvice versa, it is ynecessary to execute a drive in both units. In mypresent application v I demonstrate a form of shift control whereinpredetermined sequence of alternate change in the two forward drivingunits yields a full range of rtios under given driving `circumstances. lIn the second ilpplication noted above are l shown improvementsproviding smoothness of shift from one ratio to another, and a degree ofl For a shift from second tofthird, for example, a change in both unitsis required. The

alternatives of opening the torque path in one unit, making theshift inthe second unit during the no-drive or low torque period of the first,and completion of shift in the first unit; or else making the effort toestablish a nearly simultaneous shift in both units are herewithdemonstrated.

-The complications of sequence controls so'as to shift operation in bothforward. driving units is achieved for advantagesin a measured changespeed interval, quickly established 'and completed.

Inertia absorption means are. also shown to provide speed changeinterval under torque for quietness` and v.shockless transfer to a newdriving condition.

As has been discussed in my preceding cases,

automatically operable orfself-changing gearing consist of twoordinarytypes; first-, wherein the no-drive interval of shift isestablished by opening of a main clutch; and second, wherein the mainvclutch need not be manipulated, the elements within the transmissionproviding all of the essentials for the no-drive or low torqueinterval.My invention discloses the latter as an example, however, withimprovements in simplicity over the rst noted, and a resulting economyin the number of parts.'`

In the preferred construction of S. N. 45,184

` noted preceding, the invention is shown embodied in a formof changespeed gear Aunit which is 'utilized' by itself as avratio lchangerbetween a prime mover,; clutch v,and a load to be driven; or

" else included in a grouped assembly of change speed devices operatingbetween a power and a l load shaft'. While the example showing is in theform of epicyclic gearings having alternate torque paths, one being adirect` drive, others' through f gearing of planetary form, the frictionelements ,c simultaneous or nearly simultaneous 'shift inV mul- (i0Ithroughgearing. mayequally .be `used to connect used to connect directdrive and-to set up drive 2 I parallel clutches in common four-speedconstant mesh gearboxes, within the purview of .my invention.

A feature of my invention is the simplified manner of automatic controlhaving overriding master control means to set aside automatic selectionand compel shift o drive to a desired driving ratio, through measuredtorque capacity proportioned to torque demand.

regime yielding correlated functional speed ratio' changes whereindoubly-compounded speed effacts are obtained.

Additional features or novelty in my disclosure y as regards auxiliarypower supply, alternate' measured actuation of selected speed ratiocomassocie Figure il. shows the differential valve of Figure 9 indetail.

- Figure 12 is ve. view ofthe porting o1 the automatic pressure valve208 of Figure 9, as in running condition.

Figure 13 is a view similar to those of Figures 6 and 'l' of theinterlocking lever controls, but illustrating modifications by whichtheoperator may enforce continuous drive in third speed within apredetermined speed range. Figure 14 describes the' modifications in thecontrols at the drivers `position for the modications 0f Fig# peilingand actuating mechanism, reciprocal and j coordinate automatic controlstherefor, involving combinations of driver will, driving conditions, andmaster selection controls capable not only of superseding automaticallyselected speed ratio settings, but also invoivingproportional torquecapacity measured according to torque demand, will be apparent uponinspection of the follow-f ing specication, claimed and illustrated inthe accompanying drawings, in which;

Figure 1 is an elevation section of the forwardneutral-reverse gearshowing the drive to the servo pump system, the lubrication porting andthe shifter mechanism for the primary shift geering controls.

Figure la is a similar view toFigure 1 o the general transmissionassembly structure with the casing broken away at the bottom. Y

Figure 2 shows a vertical cross section of the double drive to the servopump @stem taken at 2--2 of Figure 1;

Figure 3 is a vertical'cross section taken at 3--3 Figure l5 is arepresentation of a modication of the differential control valve ofFigures 6, 9 and l1, wherein the relative pressure operated sleeve isomitted, and themovable valve is a unitary member.

In Fig. 1 the vertical longitudinal section of the transmissionstrdcture shows the general relationships of the gearing and drivingelements. with the forward-neutral-reverse gear unit at the right.

The main clutch bell housing i is attached to the transmission casing 2by bolts Web 4 separates the forward-reverse unit from the rest of thetransmission, 'whichv is substantially as in S. N. 45,184 notedpreceding. and shown also in section in Figure 1o.

The main clutch driven shaft 5 is supported in the casing 2 by ballbearing 6, and input gear i is fixed non-rotatably thereto. The splinedshaft t of the forward-reverse unit pilots the forward Driven shaft icarries drum Il, the inner surn face of which is internally toothed atI2 to form the input ring gear of the "frontj unit. Bearing of Figure 1showing the special relations ofthe A 'and drive for theautomatic ratioshifting system. v

Figure i shows an elevation cross section at tuation system of the rearAunit is described.

Figures 5 and 5a, 5b and 5c, describe the clutch ytershaft gear body 2Bconstantly lmeshes with l in web i supports shaft 8 in the casing 2.

The oountershaft i5 is non-rotatably supported in casing '2 and web 4.The countershaft gear body 2o rotates on. bearings M on the countershaftla The rst gear element I l of the couns a of Figure 1a, mwmen me gearedinve ca plates 33Q$0 and 38-55 of the front and rear l units of la,which provide direct drive coupling. Figure a'is a section of theexternally keyed clutch plates 36 and 5.5, suchjas shown 'in section inFigure la.

Figure 6 1s a schematic dravinsof the entire erally from 'the left sideof the vehicle in which my installation is, shown as an example. Thisview traces-out all of the control functions, both manual and automatic:Figures 7 and 8 being enlarged views of the interlocking control. leversystem and the valving for the'front and rear units respectively. y

Figure 9 is of a schematic control erstem-simi-4 control and shiftactuation system as seen gen' lar to Figure sembodymg modifications Verthe controls and actuation members wherein a, closer coupledfintegrationover the degree of drive is maintained by the manual control elementslthan Y in the system of Figure 6.

The second countershaft gear element i1 is 'constantly meshed withreverse idler i8 supported, .-ineasing i. The reverse idler gear i8 mayalso lbe mashed with sliding gear I9. splined to and slidable on splines9 of-shaft t. The teeth of i9 are meshable with teeth If of gear l,

Bushing B9 pilots shaft I in shaft 5 and integral gear. l.' e

Thrust bearing 41, similar to i0 and I0' transfersthrusts between shaftIl and shaft 50 carried in the casingon bearing Il. The extension ofshaft 50 acts as a carrier for planets 43 spindied en shafts Il; asshown in Figure 1a.

The transmission lubrication and servo pump rotors. Ill and i12 of thecompound pump assem-k bly to be described later, are driven, one bycountershaft gear: body 20, the other' by shaft 8. The

compound pump -operates constantly, whenever rotational `power isapplied to'clutch driven. shaft 5, or to shaft 8, by-virtueof gears i"andlli,

rotating with the shafts respectively.

Ashan; z| ls spuned to carrier zz -of the from" unit, and is piloted a;the `front end in shaft 8, and at the rear inthe outputshaft (not shown)Portedoil pssagesdeliver servo and lubrication oil pressure -to thevarious' units as has-been described. Shatt 2| is the'power outputmember ln Figure Fixed to planet pinions 24. .Pinions 24 constantly meshwith the linner toothed ring I2 of drum' Il, andv with sun gear 25. Thelatter is integral with carrier 22. shafts 23.

Governor drive parts are-shown in Figure 3 in relation lto the gearingof Figure fl. In the rearunit the arrangement of elements 11s as shownin s. N. 45,184, except as noted in j the improvements in the presentcase. The ele-- vation section of Figure 1a is a schematic view of thetransmission structure according. to the case noted.

In Figure la, the unitary assembly in section is given, with theidentifying parts of Figure 1 in the forward-neutral reverse unitduplicated.

, ases, for' the :rent unit. *me resrlumtis not'siwwn earner 2zare-spindle' enfans? 2,3' `for sleeve 26 rotating on bearings 21 of thesleeve of- `Pinions 24 rotate on bearings 23' on and 39 respectively.These are preferably fI steel, and prei'ormedin conical shape, in order'.tol assist release when iluid pressure is remved for disengagement.' Ithas been found inl practice thatv multiple disc clutches under pressure"have an unpleasantdrag unless-sumcient energy .is stored in the clutchplates tobreak the compressed oil film through progressive shear forcesuch -as afforded by this construction.v 'I'his Amethod of releasecontrol is believed novel.

The action of engagement in a clutch such as at'33 '38 is iirst foriluid pressure to ilow in 218 and 19, Figureia, tomove piston-12 againstthe Theeso-called front unit is that one immediately adjacent theforward-neutralreverse gear, and' consists of a planetary, two-speedgear, brake.l clutch operated, the brake applied by springs, regulatedby @utilow of-fiuid pressure, and the clutch appliedl by fiuidpressure.Y

' Bolt 32 in Fisurel is a' clamping means for the members" 29and 30 ofthe reaction drum of the front unit as shown in `Figure la. The web ofreaction sleeve 2 2is'riveted at 3| to hub 34 splined conoidal discVspring action of-clutch plates and releasing springs 8 8` As will bedescribed later, the servo pumps of given speed-range capacityworkagainst a resistance afforded by thebrake springs 491 and 91a inaddition to the above noted spring actions, which determine theregulated atA for plates 332 Plates 36 are .apertured to V permitpassage of the bolts, as in Figure 5b.

The 'structure is; output shaft 2|, keyed or' splined' to carrier 22extended to support clutch plates'- 33, having spindles 23 vfor planets24, reaction sun gear 25 being affixed by sleeve 26 to brake drum 28extended at 30and serving as a-I mount for presser plate 14, clutchreleasing springs 88 and Vplates 36. The drum 28 is recessed incylinders 1| `for pistons 12 having pins 13, passage Hopening to th.:cylinders from gland 289 to which pipe 218 leads by passage 2^8'|. fShaft 2| is the inp' t member for, the so-called ability of the clutchesa torque carrying mech.

anism.

As described thus far, the clutch will of neces-v sity need to carryengine torque times a design factor, lancithe` vfluid pressure rangeneeded tol furnishdirect driving torque will depend upon theservopumpgnet speed component. Later will be explained the means whereby theclutch capacity may be varied by changes in the torque demand) andvariations in ratio,` yielding accommodation. to driving conditions forsmooth operation in which thenet line pressure in cylinders 1|, forexample, may be low foi-'initial -drive when the clutch torque capacityrequirements are low, and higher when the requirements are higher. Fromthese initial points. the building -up of clutch pressure to maximumengagement pressure proceeds on a predetermined scale commensurate withthe availableline pressure,l conrear unit, and has integral sun gears 31and 38A meshing with planets 43 and 44 respectively.

Output shaft 50 is integralwith carrier 45 oi planets 43; f and annulus5| which constantly meshes/,internallywith planets 43 is joined bydrum52 to carrier E4 for planets 44-which constantly mesh withannulus.42 rotating'with drum.

39 on which brake 90 may bear.-

omteh drum 5s is keyed tev rotate with' Sheri 2|, and is splined forclutch vplates 60. .Springs 89 are release biasing means'for clutch 55and k60, the plates beingkeyedto rotate with drum the lclutch plates,andv the volume of oil which` does not intersect the internal teeth 6|,but the ditioned by the resistances acting against the pumps. 1 v

In Figure 5 scores 92, 93 in plate 33 are spirally c ut in sections asshown in Figure 5a, wherein a predetermined ratio of contact surfacebetween can be" retained in the scores, is established. In the example,lthe innermost land ofthe scores "outermostland likewise does intersectthe outer e edge. The scores may. serve asl adiat reservoir 39,`extended at 56, in which. portion clutch cyl:

ing against presser plate 18. N,lfassage 19` feeds 'unit porting, for

clutch actuation by i'luid pressure.

inders 15"mount pistons 1 0, piston pins 1'Ibearfrom leads in glandmember similarly to the front l Thebrakesw and 90 are similar inconstruction, self-wrapping being negligible, the arrangement being asin Figure 4. The clutch plates are- `so designed that a definiteamount-oi' lubricant is maintained on the engaging driving faces after`preliminary engagement. In Figure 5,"the in- .ternally splined platev isshown spirally sc ored in a manner such ythat under presure, .excesslubricatingoil squirts out at the periphery. yet a considerable volume.of trapped oil remains in the score cuts, as willfbe clear byinspection of Figure 5a., 'Infthe .Figure 1a, plates-and 90 are soconstructed, and theseare preferably of hardened bronzeorsimilar'material The scores may inof oil. when' the clutchsystem33-38is engaged. Bolt 64 is a clamp bolt for the drum parts, similar to bolt32, and is also a key boltfor anchoring;- -plates 39 against rotationalmotion with respect to the drum.

The ratio shifting controls integral with the transmission assembly`areas follows. In theforward-reverse unit.' slider lgear I9 may occupy-three positions; forward drive when clutched to teethJ of gear 1,neutral, and reverse drive when meshed with reverse idler gear |8. Yoke|00 is integral'with-member |04mounted'on rod |0| and controlled:through arm |02 and shaft |03. This linkage is also shown in. Figures 3and 6..

By wayt of illustratlon,. in Figure 4isy shown anchored incasing' 2, oneend ofbrake element i 9 9.".Pin 92, lockedby a; nut 92a, engagesthesocket of anchor piece 9|. The opposite end 33 'of brake 90 is pivotedat 90a to thrust rod |90. This brake element as shownconsists-of asingle turn wrapped so that upon actuation when the vunit is operating.a minimum of self-energis'ing tersect the external margin, or theinternal spline cuts; .or stop short voi intersection-at both points.Figure 5b shows the detaiiot clutch plates 39' Y and 85, externallykeyed to rotatewith drums 28 force exists. Pre-set or pre-energisedsprings, held ofi by the fluid pressure system and controls tofhedescribed, are eiiective to actuate thebrake at controlled rates. Thedetail of the servo system is shown in Figure 6. The brake 800! thefront unit is identically constructed, andinternally arranged as inFigure 6.

Clutch 55-60 as in Figure 1a couples reaction drlin 39 to allait 2| toestablish direct drive in the rear-unit, and brake 90 prevents rotationor 10 drum 39 and annulus gear 42 to establish geared drive. The clutchdetail is given in Figure 5. Similarly, clutch 33-36 couples clutch drum28 to drum 34 for direct drive in the front unit, and brake 80 attachedto casing 2, and worked by piston rod 280, establishes geared drive.(See Figures 4 and 9.)

i Ratio Front unit i Rearunu. 1 3.375/1. sduction' l Reduction. 2 2.25/1Direct i 3 1.5/1.. Berlusconi Direct. 411/1,... Direc: ne.

For example, with reduction ratios of 1.5 to 1 in the forward unit', and2.25 to l in the rear unit, the overall lowest ratio available would be3.375.

The next lowest ratio would be 2.25 to 1, obtained by keeping the rearunit in reduction, and shifting the front unit td direct. -Now if weshift the rear unit to direct, andthe front unit to geared drive, weobtain a net overall reduction of 1.5 to i. Direeedive 1n been 'umtsyields im l, all elements rotating together. It is entirely feasible toobtain all of those ratios superimposed on the reverse drive gear ratio,but is unnecessary for passenger car purposes.

In Figure 6, recessed in cylinders 7i inange 29 of drum 28 are clutchpistons 12, guided by pins 13 in presser plate 16. Similarly, cylinders15 in web 5S of drum 39 are fitted .with pistons i6 guided bygpins 11 inprser plate 18. Drilled passages i9 lead to cylinders 1| and passages19' lead to cylinders v15.

Lubrication and .s'eroo system The main supply of transmissionlubricating oil for all three transmission units is kept in the sump 2|9. The main drive for the double pump h by means of element 20 .to whichpump rotor gear |13 is tlxed.'and shaft |10. -Thefpump is. operating atall times whenever either shaft 5 or shaft 8 are running by virtue ofthe drive transmitted through gears |13 and |14.' The construction isshown n-Figures 1i, 2, and 3.

Passage 22| receives .lubrication cil from pump line 220 shown inFigures 9 and 12, delivering to ports 22|, 223.` 224, 225- and220,..from whence it is` i'ed under pressure to the various bearings andgear elements. Y

Figui-e2 shows-the detail of the drive to theservo comp Gear m fixed toshaft l drives gear coupling "|15 in which is socketed governor shaft124| and `the=secondary rotor shaft |16 of the servo' lpump. -li'or-Aall forward 'rotations of shaft `fthe secondary pumpA assembly |80produces sev positive pressure, but for negative rotations, its rotationsubtracts from the net line pressure pro-I duced 'by primary pumpassembly |19.

Gear |13 affixed to couitershaft body 20 drives gear |11 of hollow shaft|18, lwhich drives .the rotor |1| of primarypumpunit |19.

As noted in Figure 3, the primary rotor |1| drives idler gear |82, andthe secondary rotor 12V drives idler gear |83. -For all rotations 4ofthe engine connected shaft 5, primary pump unit |19 furnishes positivepressure, even'when shaft 0 revolves in reverse. See diagram, right, inFigure 9.

V"i'he suction space |10 of the -pump feeds from pipe |9 of Figure 3 anddelivers through both gear discharge orifices |84 and |85 to pressurespace |95 from which the main i'eed is delivered to ports 202 and 205 ofthe automatic pressure control valve 200, shown in Figures 9 and 12.

Pump suction is exerted at space |10 because of the well-known eiect ofgear pumps, and pressure is developed as long as either of the tworotors receives drive through the described gearing paths. Driving inreverse does affect slightly the positive net deliveryI of pressure bythe pump, since the pump unit driven by gear |14 is of smaller capacity,and may rob the other unit. The outward flow of oil is best seen inFigure 9 where pressure space |95 opens to passages |88 and |01. Valvecylinder body |98 may be built into the casing -2 or separatelyattached.Valve `member 200 moves back and'iorth -in ported passage 99, .held by`spring 20| in the "down position, asin Figure 9, and lifted by pressurefurnished by the pump through milled leads 98 and |91.

` The valve member 200 is a ground fit in this passage iBS. to formseats between the ports which will now be' enumerated; port 202 'at thelower position, open to lead |96 'from the pump;

port 202 connected .to the servo pressure main 238; port 204 to thetransmission lubrication main 220; part 205 to pump port |91; and port20B to the exhaust outlet valve 2|1. Stop danse 2 01 airords a seat forspring 20 I. Valve member; 200has a. longitudinal passage 208 out partway of boss 2|4, which in the lowermost position is clear of the 'bottomof port 202, for obtaining initial pressure lift against vspring 20|..Assuming an increase of pressure in the pump, valve member 200 will risees pressure As the upper edge/of 20 Passes the lower limi of port 203,valve member200 has already ex- 'posed port 204, the fluid pressureVfrom lead |81 now being delivered through port 203 tothe servo pressureline. Further increase in Vpressure lifts 298 past port 204 whence both204 and 203 are served by the valve member 200 in the new posi- 6 tion.

Figure 12 shows .the normal' running position of the valve 200 with 205exposedfor balancing. effect. A decreasein pump pressure below a mini-Amum causes pressure above and below boss 2|4to become less than-.theforce of spring 20|, and less than the brake spring pressure so thatvalve 200 dumps the oil from'the servo line into thelubricationmain220fi 'f At extreme operating speeds, the pump maydevelop more than the required pressures .Therefore, valve`200 "will gotothe extreme- "up position, with spring 20| 'fully compressed;l At thissetting,- abutment 2 is opposite the upper-limit ofrelief port 200.

' Over pressure from lead. |91 Vmaye'scape direct builds up behindabutment 2 0.

aso'asis to port 244,' to tlie transmission sui'np by reliei' valve 2|1.At high speed the relief action -occurs wheneverv the pressurerequirement J isexceeded.butno disconcerting change in the.

operators control over the servo mechanism oci* 5 Some of the advantagesof this valve and porting combinationvare that "it maintains uniformservo line pressure, yields a positivevserv'o cutoff .at a given-minimumpump pressure, and protects l transmission assembly: a useful commercialfeas ture for avoiding excessive wear and heat. y The particulargrouping of 'the porting of the automatic pressure valve in thepresentcombinal tion provides a--new characteristic extending the range vofutility of controls provided by the valve restare in this eonstmetion'is the. is

kexiiiiiiiie' 'of so pouas'vaive zito 'has admitted 'pressure to line22h-.which pressure is now avail# l able to brake' piston zall andclutch pistons is.

In a given interval, pressure' in 238 will rise until a brake Isli .willrelease, and clutch 55 and 6o will endpoint 'of brake release.

'l .At the same time the governor operated valve. |50 may be in either.the right or leit'position, de-

pending upon. the coaction of pin and lever |||,.and if inthe right ordirect drive position,

- the building up zo: iinepressure in zas win e150 cause actuation nfbrake piston 28| and. clutch pistons 12 of the front unit., It will beseen that -automatic ratio upshift. If the handlever 30| were in the lowposition, valve |58 would, of course, be inactive, and changer-up inratio could only occur in the front unit', by presetting of valve"|50.

Automatic downshift therefore can occur as a complement to th'eabovedescribed action, .by movement of valve 200, the relief of lpressure be-Qing controlled by two means; rst, through' action. The grund'fitting.of valve :on 1n bore 25 "dumping of line pressure into the lubricationline |99 is suiilciently loose so that a continuous vleak- L,

age of pressure The graduated effect of this leakage, coupled with therestriction 'passage 208, the related capacities of brakeand-clutchcylinders, and the force'of brakesprings, combine so to yield anet response suitable for establishing;4 changes of speed ratio variedby pump pressure.. For example, with not sufficient pressure in line23s. to' sustain clutching-inthe 'iront and rear units, theirbrakesprings-lockthe brakes to es-f tablish low-low, orllowest forwarddriving speed ratio. Provided 'the other valve controls are set todeliver pressure to the front and rear unit systems, an increase of pumppressure lifts, valve 200 to a point where boss 2|4 blocks port 204,Vi0v preceding the uncovering of port 205 by abutment 2li.v Spring 20|'is preset ,to yield for a given set of pressure conditions such thatwhen the valve 24|. passes from initial-to running cons dition, thereisl a -rapid build-up of `servo line 45 pressure at the medium lowspeedsof the pump.'

at which capacity is ample tol operate the fluid servomotors of both thefront and rear units.

Therefore; if the further', ratio control valuing is set to admit servaline pressure from 222 to either or both of .the front and rear units,thespeed ratio of drive will change up to second or to higher speedratios, establishedl by variations of pump pressure and controlled byautomatic 5 5 passage 22| in web 4 of housing 2 'of Figures i and la.Oil may flow lfreelyfrom 22 to annular channel 2 22 cut'in the externalportion of hollow shaft .4 of gear I2. .Drilled holes 223 connectingvalve 200. In this casethe 'settingsof valves |04 Vand may be consideredas preselected. with actual selection determined by valve 204. Inthlsevent, the engine speed at which .the `operator determines to drive,the'ability oi! the engine to.' handle the existing load,'and theresuitingspeed of shaft 2 arethe factors which control the criticalpressure for speed ratio upshift. s t

Inlet port 244 delivers fluid pressure from line ,238 and line 212 tovalve |50. Relief port 242, 6^ opening tov umn-may beequipped withas'selffloaded/relief valve such as 2|1 in Figures 9 and A2, formetering the rate of clutchrelease and brake engagement-asis obviousfrom thev construction. `Ilurther port 202 relievesthe end of' valvei|50, lfreeing the movement from suction, to

220, and second, by reason of the metering action of check valve 2|!pivoted at 2|0,h'aving metering'fport221, and mounted to respond to backpressure dow toward the. pump from the servomotors. and to swing clearwhen the pump pressure is positive. As soon as pumnpressure falls, 'therelease 'rate of pressure from the servo "system is controlled bymetering port 221, while the orifice capacities of ,204, andthe valvespace between 2|| tive. j y

'I'he latter expedient cushions the do'wnshift .action by letting on'thebrakev springs 91 and `81 loads; e

The pressure at'which the valve releases the servo lines is preset byadjustment of screw 11t- Conduit 220 connects to passage 22| inweb4 ofhousing 2. Oli may flow freely from 22| to annular channel 222 out intheexternal portion,- of hollow shaft 4 of gear I2. Drilled holes 223connecting tochannel 222 feed oiltothe passages. 224 transverse of shaft2|. Longitudinal passages in shaft 2| furnish iubricaiitto the gears ofboth e .the front-and rear units.

enduit :n r Figures s and `12 connects to tojihannel 222 feed oil to thepassages 224 transcomme 'or-shaft 2|. Longitudinal passage 22s in shaft2| carries lubricant to thegears ofboth the automatic and manual units.The thrust bearing I0 located between shafts. 0 and -2| is oiled throughhole 220. .is

Bide cut passage 221 in shaft 2| delivers 'oil from passage'225 to aseries of 'drilled outlets 220 in the sleeve of carrier 22 and a seriesof drilled outlets 224' through the shank' 25 of reaction sun gear l 25.Oil may flow axially through splines 229 to the space between the web ofcarrier l22 and the adjacentface oi drum il tqteetii l2 and' planetgears 2,4. Oil alscpasses through bearings 21 to the teeth of sun gear25; by washer 200.`

Drain out of such oil under pressure nds its we! back'tothe sump 2|. theopening of clutch valve 200 does, under'these circumstances, afford4boss 2|4slikewise becomes eilecgradually, preventing sudden,deceleration shock y u cushioning action.

drums 28 and 34. y

The volume of oil trapped within the drums 28 2,362,418 ca -as relievingthe accumulated oii inside the" driven by the engnauntil the main clutchis disengaged, and Acar motion will also drive pump and 34 in the spaceoccupied in part bythe plates 33 and 3S requires a given time to berelieved,

since when the clutch pistons 12, 'IE are actuated,

the leakage effect occurs at a known rate, yielding Side-cut outlet 232connects passage 225 so as tolubricate thrust washers. and 65 and themeshing teeth of gears 38 4and de. drilled outlet 235 delivers oil tothe teeth of meshing gears 31 and 43. A thirdsoutiet 236 feeds oil tobearing 231 and it passes from that point to drilled hole 238 in'shaft59 to bearing 40 between the sleeve of drum 51 and the shaft 53. Bearing49 in web 48 receives oil from this pressure source. Drain out of suchlubricant; oil under pressure finds its way backto the sump 2l9, theclosing oi the direct drive lements of the clutch relieving theaccumulated oil in the drums.

The forward-reverse` unit 'obtains oil under.'

Similarly;

pressure from the passages shown. Further lubrication of the unit is bycustomary dip in the sump oil. The compartment constructionoi casing 2maires it possible to seal the. entire assembly with oil pan23l, whichacts as an oil reservoir, sealing means ZIE providing a. tight joint atall contact points.

The use of a common sump for' the gear units and the servo actuatorsyields advantages for low leakage losses', lrapid re-ciroulation, Vandmaingear |111.

It is not possible to withhold drive from the Dump, at anytime wheneither engine or vehicle are in motion.

The automatic speed ratio controls for the op` eration i of the frontunit comprise, first, H3,

moved by the governor toward the left in Figures .6 and 7 as 'enginespeed increases, and pivoted to equalizer-bar lil .at lf2.

The opposite end of the equalizer bar l|-| is pivoted to toggle shifterrod l3 at. |36, and near its center, notch Hd is engaged by pin ||5setin lost motion lever H3. The latter lever rotates on shaft |23 as acenter; carries springstop ||1 and also arm 23. a Opposing spring stopH9 is integral with leve |2|, also rotatable on shaft |26, and havingeyelet |21. Intermediate spring |25 transmits forces in compressionbetween levers |2| and H6, the` spring. stops il@ and i'll'preventingthe spring' Lever |32 mounted external to theV compartlment |26.rotatable vwith shaft |20, is pivoted to tenance of proper capacityrequirementsf and provides one-fill service oil replacement. Theresistance drop ofthe circuit of oil pressure mains is arranged so thatat slow engine speeds, as at rod 36| 'and |3, and responds to theaccelerator pedal movement.

At a given position of governor link pivot H2,

f lever |32 may rotate about center 28'counter-- idling, fresh oil ispumped through the' tran's-v mission units, available the instant theengine starts up, since the main oil pump gear |13 is constantly drivenfromthe main clutch driven shaft 5 through gears 1--IBL To relieve thedriver or Servicer from learning new modes of operation, I arrange theservo mechanism so that when the car is standing still, the driver maywarm up a lcold engine by holding the customary main clutch pedal indisengagclockwise, rotating lever |3| and pin lm causng arm `2| andspring stop ||9j to'compress spring |25 applying an increasing force tocause corre.- spending motion ofv |16. H5 thereupon exerts a leftwardforce uponequalizerbar and on link lever i i3 attached toit at pivot|36.

-An increase in governor speed will tend to shift pivot |36 to theright, lever tulcruming at motion.

ing position. 'Ihis'operation may be carried on without forcing oilunnecessarily through the servo system.

The novel nature of the double pump system is an: essential feature ofmy invention. Since shafts 5 and 8 may rotate at different speeds,

and in opposite relative directions, and since it is desirable tofurnish oil pressure at all times whenever any rotation whatever isimparted to the variable speed gearing; and further that it isadvantageous to arrange themechanism so that no operators whim mayinterfere with the circulation of oil whenever the `related portions vofthe gearing may be rotating under either engine rotation or vehiclemotion, I have herein created an H4, tending to counteract the abovementioned 5 .Lz Casing extension supports levers |33 and |39 at pivot|31.

fOn xed pivot |31-toggle arms A|33 and |33 are mounted, the lower armIBIbeing attached to pivot coupling |43. The engagingfe'nd of link leverH3 coacts'with coupling I". assisted by spring |4| stressed betweenguide' lugV |43 and the pin |43 on link lever ||3. .Thus a rightwardlyexerted force in rod Hl acts on coupling Ill to cause arm |38 to swingcounterclockwise about exea pivotisi. l

oil supply system fullling these requirements l by combining therotation of these shafts in. a

driving system to a'double unit pump of the. augmenting type, stagedfor-one vrange of pres-3 suresior forward drlveand for another rangeproviding ader ofpressures for reverse drive, yet quate pressures inboth ranges. This form of pump, and drive system, is believed novel, andof unusual commercial utility.

When the car is in motion, whether or not :law

wayssupply servo and lubrication pressure. the jawclutches aredisengaged by shift of the hand lever v30| to neutral, the

pumpstiliwill'b'e- The upper arm |39 of the toggle is yoked to valvebody |50 by loose pivot l, .and alsoat `its upper end, carriesweightedpivot i :Toggle spring |43 attached toarms |39 at |49 and |45respectively, stores energy for snapping the valve right or left, aspivot Il! of arm |38 is moved -past center with relationship to iixedpivot |31 and pivot |45 of arm |39.

when valve body :sa is in che rigntnand pos ition as will be seen later,uid; pressure is admitted to hold oi brake 83 and engage the clutch33--35 of the front unit. When it is in the left hand position, the uidpressure of that system is released and the front'unit is p ut in lowgear drive by/ springs 31andl1a actuating brake band `30, throughrod283, rocker-333 and thrust rod similarto |93 inEigure 4.

Piate m rotating wahrhaft :5 2 is rocked bymaand.

movement of externally `mounted lever attached to shaft |52. The latterlever is Joined to rod 3|0 'at p ivot |53, and selection' movement ofhand lever 30|v of Figure 6 acts to shift lever |5| to operator-selectedpositions, through 3 |0,'

'pivots 0|| and 300, rod 300, 'clevis pivot 301,

\ curved 'arm 300, shaft 305, .andlever 30|.

The valve |50 of Figs. 6 and 8 is shown in the .left-hand position,connecting ports -201-.200, and isolating'ports 209 and 200. Pressure.from,

pump line 230 is therefore shut oil',` and no 'servo pressure. may beexerted to take oif the front unit the required towing torque.

brake 00 'and apply load to clutch 33-.30, the..

`front unit then being in its reduction drive, or 10I-n y .x r, I y VThe applicationfof thrust-rightward by rod |I 3 #snaps the toggle lss-mto the opposite position, by stretching spring |40, andthe valve .|50

seals off port 201 from exhaust, admitting pump pressure to release thefrnt unit brake and apply the clutch, for .direct or top gear ratio.`

- Spring |4| normally biases the toggle 13B-|30 for this condition;however, the -lever of Fig.'

.'1 fulcrums about pin |15, movable by the throttle and manual shiftcontrol mechanism, and being pivoted 'to governor rod 0, is subject tospeed generated 'force from governor weights 25| and springs 252, 253,254 of Fig; 3.

The toggle arms |30, |'pivot at'l31 on an extension |05 of the valvecasing, as shown in Fig. 8. The l`toggle mechanism of Figs. 6 and 8 -istherefore in'its left-hand position, for su`stain.

ing low or reduction drive in the front unit.

to shift ratio in the rear unit t'o direct,

Positioning lever |05 attached governor' rod The rear' unit'v'alve |08of Figs. 6 and 8 rec eivespumpline pressure in port 203, anddelivers'sameto port 202 and line A 212, for vtaking 1 'off brake 00of'the rear unit and applying the' 0 clutch 55-00 thereof, for shift..from reduction to top gear'drive in that unit. 'In its up.posi tion,.as shown, the pump port 203 is sealed, and the servo port 202A is opento exhaust at 200; and

in its .down position, the brakeis taken og'ana,

the clutch applied. The valve |00 therefore establishes 1ow". when it isup, and direct when it is.down, and the fork 290 of lever |00 in Fig.vrl'is movedv by pin-|59 giuded by slot |55 When the, pin |50 liesnearest to the center of motion of shaft |52.radially, the valve '|08isup orin low position; and conversely in direct when it is down ,Thehandlever 30| of Fig.' 6 in R position rocks shaft |03 to position thereverse gear I0 of Fig. 1 to mesh with gear 8, and at .the same timepulls rod 3|0 and leve'i` |5| to the left to rock plate .|20 clockwise,the hook |50 swinging to block toggle arm |30 in -the' position' shownin The interaction, of 'follower' |23' of lever |23 integral with ||0 isused to prevent downshift of thefront unitwhen the handlever 30| is inlow, cam |20. restrainingclockwise motion of' |23 of Figure 7.Resumption of high drive restores e coaction by moving cam |20 out ofcontact ith follower |23', whereupon the latter is .free 'and automaticshift action is resumed.

`Irregular cam slot- |55 cut in cam plate '|20 actuates the, valve'` |00connected with the operation of the rear unit. Hoo1 |50 acts'as a stoptengaging with-toggle arm head |.45 to prevent i's the automatic shift'lockout mechanism..

|00 in its low or up position, permitting brak -soto heineken.

l Servo controls These control linkagesv may be mounted on the left sideofthe transmissioncasingsuperimposed upon the valve casting, asvindicated schematically wth 'the governor mechanism .at 'the left;y andat .the rightthe taggle'suppoit- |65 for ipivot m..

automaticshift to high ratio in the front unit, .when the`plate'l20 isin reverse position.

Lever |00 pivoted at |58 mo'ves manual' valvel |00 at yoke-200 andcarries pin 00 which iits cam slot4 |55 of cam plate` |20. The centersof |52 and lavare taken with respect to the arm Q 'H0- |59 and the radiiof slot distances 'from center |52 so that movement of arm |.5I by rod3|'0- forces lever- |00 to follow clockwise. motion of lever |5|,\actuating manual valve |03 of .the

rear unit, for 'shift to low,for counterclockwise for direct Valve |00movedby lever .|00 through yoke200 follows .the movement of lever |5|-.The cam slot |55 which moves pin |50 ofi|00 is arranged to-es.-tablishthe valve |00 inthe 'following positions:

Valve Ratio' i 'Handshift w. High.

yItwill` be noted that .the rear-.unit is n'aintained in direct drivecondition inneutral. This enables the driver of 'a car with a stalledengine the shaft 0 turns over be'causeiof car motion, pump drive throughgear |14builds up pressure to. obtain an easy start by towing,'foras sonas The downward extension ofthe valve case casting terminates at theright'in 'guide lugs |43, between which lever link |13 is constrainedto' m'ove." Pivot pin- |58 projects toward the eye' of. the observer andis a mounting for lever |00.l

.The -manual control valve |00moves in .bore |01; uppermost port, 200,relieves fluid pressure fr'om the cylindrical spacef 20|,. dumping theoil'back into the external portion o f the housing, from whence itdrains back'to the sump 2|0 of 'the transmission. TheV second port, 202,leads to the outlet of the casing, 'from where the oill y may iipw,through line 212 'to the. control cylinder 252 for the 'rear u nit. Thevport 203 below is A the inlet from Athe servo pump, and it receives oilfrom passage 213 through the'porting shown. The port '254, deliversfluid pressure to passage '1211,J'from where it"'is used lto compensatefor4 brake releasing action of springs 01 and 01a.v Straps 203cover-cylinders A2 02.ar 1d 202,' as retainers for the spring'assemblies shown.v

1 When the valve |00 is in thelowermostposition, the pressure fromtheservo is admitted to .thus compensa ing for existing vline' pressure in210, forfregula ing vthe torque capacity of clutch 55 and 00,'as will beexplained. Whenthe valve |00 is -in the upper potltiom' it cuts oifthepresf- A sure from the line 282-212 and drains ports204 and 202. 'Thisis accomplished when the hand i leve'r 30 I is placed in either 'low'orreverse,

positi9r,1 0n' the indicator. plate 302;, Duringdownshift from4 vdirect:to low speed ratio in the rear Lunit, 'this port relationshipiseffective,- but not when. the' vaive mis at' strokey orin the directdrive. position fluid pres.

4at'jpivot' m t9.'- lo is piyonedtothe @stinger the botten or as@ surefrom zes is admitted to port 262, and is eirectve' to overcome the forceof springs 91 and 61a exerted on brake 88, as well as exert pressureupon clutch plates and 60. 'Port 268 is effective to drain the rear unitcylinder 282 through port 262 when the valve |68 is moved control ofthe-front unit in closed position, with line 218- and port 261 open toexhaust. When valve |58 shifts tothe right-hand position, the front unitwill go to direct drive.

The mechanical movementwhicli requires thevalve to occupythe describedtwo positions is shown inFigure 6, where loose pin |48 connectsv theextension of 'valve |50 external tothe case |8| to toggle leversISS-|88.' The' two-positional action of the toggle mechanism" has beendescribed preceding.

Piston rod 28|! works 'against rocker |83piv oted at |98, movement oirocker 83 exerting thrust on thrust arm |88, whichis pivoted `to thefree end of brake band 8G ata, and the reduced end of which swivels innotch |82.

Rod 280 is fastened to abutment member 38e, which is apertured to permitpassage through it of pins 291 attached to piston 28B, whereby slidingabutment 214, on xed abutment rod 380 may receive the motion caused byfiuidpressure in 88E and 292. i

Especial attention is directed to the construction of the actuationshown in Figure 6. Springs 81, 81a, and 81o react against retainer strap283 .bolted to cylinder 282, which may be integral with transmissioncase 2 or the metai forming the compartment |26. Springs 81 and 81aexert their tension against piston 28i, which may slide freely on rod288. Spring81b normally exerts pressure -against abutment member 288raised to slide on stop rod 3'00 attached -to cap 288. Abutment member286 is rigidly attached to the end of rod 288, and may bear againstabutment member 288 to the limit of motion allowed bythe ends of rods288 and 808. I i

Compensating spring 288 bears against the inner face of-piston 28|',seating rmly againstl xed abutment'286 attached t/o rod 280 by a lockring.

spring 288 is loading piston dei to move toward point 286e is theinitial engagement stage of the .sacaste 12 and establishing drive inclutch @3P-35 of the iront unit. It will be understood that during thec. first phase of pressure increase in cylinder 282, that the firststage of pressure during which clutch, during which a -iairly'rapidbuilding up of volume is accompanied 'by a gentlerise in pressure inclutch cylinders 1l. After the abutl0 ments 286 and 288 meet,- theincrease in pressure due to the increased resistance of spring lbnowbrought into play causes a more sudden building up of pressure on theclutch plates 33 and 36, so that a graduated and increasing clutch'capacity is canbe created and sustained during the clutch engaging cyclewhen the brake release mechanisxn is operative, and thereafter when therelative motion between the sets of clutch plates ceases.

Port 2 62 connects pump line 213 and its port 263 with line 219 whenvalve '68 is in the up position' of Figure 9. Port 260 opens to sumpthrough self-loaded valve (not numbered) aixed to the casing'oicompartment |24. Port 26B joins gg the lead 216 to compensator line 211of the rear unit, corresponding to port 261, which joins 216 tocompensator line 211' forthe front unit.

In Figure 9 cam plate |26. similar to t28 of Figure 6, is mounted torotate freely on shaft 3g |20, and is moved by lever M5 attached to the35' hold the ends of spring I I 6in place.

Lever |35', movedby thegovernor, is arranged to transmit its motiontolever 426 which, in construction, may be integral with, or an extensionof |35', although in the schematic drawings, the o two levers are shownseparate, joined by a shaft pivoted on-the'housing- When the governormechanism goes to high speed position, levers |35' and 428 rockcounterclockwise .until the flat end of 420 assumes a position to blockclockwise '45 movement of lever 2|1. lShould 'the operator attempt toshift the rear'u'nit to low hy movement of lever 80| of Figurejat a timewhen governor speed is upward of 70 miles'per hour, for examr ple, lever|20 1will abut lever H1, and the cam 50 plate |28*` will not move,lalthough the handlever A of spring M6.

action will yield to the operator's eifortbecause Lost motionlever||6'oi` Fig/ure 9 is pivoted in Y the compartmentl toswing in an arc tointerfiisect the movement oflever |8|' rocking with 215 to cylinder 282may build uprapidly, being I assisted by the force stored m spring m.'when the face of piston 28| strikes the upper end of abutment 286 atpoint 286e, the two springs 81 t so drilled inlever H6'. y,

Piston I8 receives uid pressure from thisand 8111"' are overcome and theinitial positive movement 'of the brake releasing system beginsf Thecontinuing application of iluld pressure to lcylinder A282 thereaftercauses abutment 288to engage abutment 288, pressing spring 81h,Continued movement may therefore take place until the shrouded end'ofrod'288 engages the adjacent end of fixed-abutment rod 308.

shaft |20 and lever |32 connected as in Figure 6. to the acceleratorpedal 803. Fluid pressure from 212 and 218 is led through line 4|!) toapertured bushing 4H and through line t I2 cored and system,l line H2opening to cylinder IH in which piston I3 is mounted, so that wheneverthe rear Aunit is in direct drive, the clearance distance bee5 tween theend of lever |3|' and the fbase'of'piston M8 becomes less. and the netdistance moved bythe pedal connected lever |8|' is less, before aresulting response of lever H8"v .to pedal motion is had. ,i The passageof clutch fluid pressure from cylinner 2s: ef theY front uniaews through21s, and 19 to cylinders 1| in drum 28. `Likewise the dow from cylinder292 of the rear unit passes through 212,V 219, and 19' to Ncylinders 1 8of existing, in une 21s'avauab1e'f9r loading pistons is' anun as.. Y

Figure 4 is a transverse vertical section through the transmissionassembly. Drum 39 ofthe rear unit is shown in position pto be gripped bybrake band 90, the fixed end of which, 9|, is-restrained from clockwisemovement by adjustable bolt 92 through the extension of housing 2. Themovable end 93 of band 93 is positioned by thrust rod |90, rocker |93and the upper end of piston rod 290,'which is attached to `piston 29|fitting into cylindrical recess 292 in the housing as in sleeve 323 willand thereby establish the `clearancedistance between sleeve 323 andvalve 320 for closing oi! space 334, when valve 320 is moved by plunger323. l

The net tension in spring 322 determined by normal setting of lever |22against plunger 323 Figure 6. Springs 31 and 91ul bear against thepiston 29| in a direction to cause brake band 93 to grip drum 39 beingsupported by base or cap 293. Subpiston 294 slides in compensatingcylinder 295 under fluid pressure supplied from the differential valve 320 described following.y The' three conditions of. operation of thisstructure are; iirst. fluid pressure may 'be introduced and the degreeof line pressure in space 334 from lead 254, establishes the gradationcharacteristic sembly-are identical with those of the rear` unit,

against the head of piston 29| to counteract the t force of springs 91and 91a and thereby release brake band- 90 from drum 39jsecond, fluidpressure admitted to subpiston .cylinder 295 may change the value of theline pressure at the moment when brake release occurs; and third, thefluid pressure may work simultaneously behind both pistons 29| and 294,providing a low line rocker 393 being the same as rocker |93, theremaining thrust rod and notch construction, likewise the same. Whereverpossible, identifying vnumbers in series pertain to similar parts havingidentical functions, It is not -deemed `necessary to show a full sectionof the. brake actuation mechanism of the front unit, because of theparpressure at the instant of brake release, which acts to limit theclutch capacity since the degree of line pressure governs the magnitudeof clutch loading.

T he latter expedient is to eliminate shock during ratio downshift atlight engine torques, and to proportionalize torque capacity to torquedemand.

The differential valve mechanism is housed in the casing 2 behind thecompartment |24, and

consists of valve 320 integral -with stem 32|, 1

pressed toward its seat by springl 322 and plunger 323, the spring andplunger force being opposed by uid pressure, as will be describedfurther.

As shown in Figure 8, the valve 320 is mounted to, slide freely in bore3|9, the extension 324 striking stop 325 at the upper limit of motion.The upper end of bore 3|3 is enlargedto accommodate ported sleeve 323,which may slide therein. Flange 321 of sleeve 323. is pressed towardseating with'the upper edge of valve 320, by spring 323 whose retainercap 329 fastened on the valve'casing is of such inner diameter as' tolimit the upward travel of sleeve 323, which latter is a form of pistonvalve.

Annular recess 333 forms a lifter port for sleeve 323, whereby fluidpressure' from line 3|3 may oppose the pressure of spring 323, andchange` the port opening between the loweredge of the sleeve 323 and theupper face of valve 320.

Transverse ports 33| insleeve 323 coincide generally with large annularspace 332 connecting to drilled passage 23A-wherein fluid pressure from232 may always be open 4to space 333; between stop 325, the interior ofsleeve 323 and the upper face of valve 320.

Annular outlet space 3 34 isof smaller diameter than sleeve 323, thusproviding a limit of downward travel therefor. Space 334 is ported at333 and 333, the passage 331 leading to counterbalancing annulus 333;and the passage 213 being connected to the compensator chamber 295 ofthe actuator. for the rear unit.

spaced between annuli 334 and 333 is the ex' haust annulus 339,'forrelieving excess pressure from space 333. Cap 323 may be of threadedform with relationship to casing 2, for variable allel identity of theparts.

The bracket 304 is shown attached to the steering column in Figure 6,forming a bearing for 'shaft 305 and a mount for sector indicator plate332. Handlever 30| attached to shaft 305`swings in an arc over positionscorresponding to high," low, neutral and reverse respectively, as markedin abbreviations on the sector plate302 of Button 3|3 is a spring-loadedlatch, hand operated, to hold lever 39| in any-of itsoperationdetermining positions.

Reciprocating motion of the le'ver results in correspondingreciprocation of the shifter rod 303, pivots 309, 3|| of lever |39, rod3|0, and pivot |53 of lever |5I as seen in Figures 6 and 7.

The -transverse section of Figures 2 and 3 shows the governor drivemechanism, the gear |15 fixed to shaft 24| meshing with gear |14 ofshaft 8.

The governer shaft24l is supported in casing bearings, and carries-afllxed hubl 244. Secured to. ilanged hub v244 are pins 245, eachrecessed under the head at 243,. to engage spring retainer plate 241.Weight arms 243 are pivoted to hub 244 at 249 and terminate in camends230 and weight ends 25|.

External large coil spring `252 rests against plate 241 and fits arecessed seat in the flange of hub 244. Internal coil spring 254likewise rests against retainer plate 2 41 and presses traveler,v

sleeve 255 to the left. This sleeve 255 is hollowed out to a bearing lltover the spindle end 256 of shaft' 24| and may slide freely axially, asythrust by the end of spring 253 acting on flange 259.

At the external end of sleeve 255 collar 251 provides connecting meansfor the external mechanism to be moved by the governor, as indicated i'nFigure 6. Normally at rest, the assembly of governor parts is as shownin, Figure 6. As appliedspeed increases,v weights 25| of arms-233 swingabout pivots 249 andl cam ends 230 shift `sleeve 253 against the tensionof spring 254.

When the sleeve has moved a predetermined distance,` the seat 233 of theflange 259 of sleeve 253 abuts end oi' spring 232,'fand further increaseof applied speedresults in weights working against the combined stressesofssprings254 and 252. It

- will be seen that'the relative travel of sleeve 255.

adjustment of the'tensionon spring'323, in' order 2 to predetermine thatpressure in line 3l3 at' which 'l5 for a given speed increment inthelatter phase is less' than in -the prior stage, the governor workingagainst an increased resistance. `Variations of governor speed above apredetermined point can create no change in the external controlmechanism, when the weights stand at wider angles to the centerline ofthe shaft 24| The collar 251 is arranged to move arm 350 Afixed to shaftof Figure 6, which latter moves arm 352 pivoted to governor rod ||0 at353. In this way axial motion of sleeve 255 is converted toreciprocating motion of governor rod H0, pivot 2 and rocking ofequalizer bar is accomplished. y

The relationship ofthe accelerator pedal and -handlever 'linkage areshown in Figure 6.

. controlled b'ythat arm to remain in the upper position of feedingfluid pressure to the rear unit.

Accelerator pedal 303 is pivoted von the fioorb oard of the driverscompartment, and r'od 355 is pivoted at 360 so 'as to be moved freely bythe pedal 303. Return spring 351 serves to restore the pedal to minimumthrottle position. Connection 353 is to the engine throttle.

The bracket shown provides a pivot for shaft 360, and lever 364 beingattached to the shaft 356, and pivoted to rod 36| at 362, Depression ofthe accelerator pedal 303 will therefore exert a thrust on rod 355,lever 359 will swing clock- Wise, and consequently rod 36| will bepulled to- Ward the left in Figure 6. This action rocks 1e.

ver |32 through fitted pivot |34, and shaft centerthe valve controllingthe front unit into the' low" position. Whenever the accelerator. pedal303 is depressed, thedescribed mechanism then establishes a tendency forvalve |50 to downshift.

The -engine carburetor is not shown, as this is believed unnecessary.

In Figure 6, the engine accelerator '-pedal 303 n rocks shaft 350through rod 355 and lever 359,

the shaft 353 being fixed to lever 353' pivoted to rod 363-to open andclose. the exigirle throttle .(notshown). Lever 3164 fixed to shaft 358is pivoted to rod-36|', in'turn-'pivoted-to lever |32 of the 'ratio'control apparatus.l Spring 351 retracts the `throttle pedaleonnectedsystem.

358 and lever 353, the rod 355 hooking into hole sition marked third Thefollowing assemblyofparts are mounted loosely in eyelet |21 ,of lever|2|, and carries extensionarm |23,withcamfollower|23'.- An adjustmentplaced at pivot 362 permits Y th service oprator to set the relationshipbe-` tween motion of the pedal 303 for a given ee'ct on the'mechanismcontrolled by-` rod 36|, and that at 35W- 363 may be set to determinethemovement of the engine throttle. so 1theta` tate on |26. Lever |3|carrisiain--I'IB which fits predetermined throttlevpedal positionprovides a given stress of spring- `|25 followedbyengagementof'abutments f||0 and l||'| of the levers 12| and lll to'suitthe`engine torque-speed curve effect of the trol.

In Figure vi3 is shown Va modification of the control structure ofFigures 6 and 7, wherein"v H, and- 3rd without moving pin |53' of arm|30 and therefore allow the rear unit valve |63 Extension |30 ofcamplate |26" rotates so as to intersect pin ||5 ofv lever |23, over therounded surface of which it may exert a camming action, shifting the pin||5 to the left, causing equalizer bar ||l to move to the left anequivalent distance to that caused by Wide open throttle through theconnections of lever |3I, pin H6, eyelet |21, lever |2|, spring |25 andlever ||6 to which` pin ||5 is attached, as4 in Figures 6 and 7.

The structure enables the operator to establish -a manually enforceddownshift to 3rd speed, which may .be maintainedindeiinitely for driv- 1ingV in gradients, with engine braking, and is also useful foracceleration demand other than provided by throttle pedal interactioncontrol with the governor mechanism.

At speeds above miles per hour, for example,l the governor may movepivot I2 so far to the left that this enforced downshift action cannotoccur, and the drive will then remain in direct in both units.

The modification in the manual controls required to accommodate for theextra motion of the enforced third shift is shown in Figure 14, whereinsector plate 302 is extended to a new po- The movement of the hand lever30| from Hto the new position in no way affects the action of the valve|68 controlling the rear unit, since slot |55' of even radius with thatof the slot |55 to the point where scribed and discussed in thepreceding cases noted in the superscription of the presentspecification.

Ihe governor connected linkage has not, however. been put out of action,but is still able to prevent abuse of engine and transmission, in thatat an extreme high speed governor-position, corresponding to apredetermined car'speed of say,

63'milcs per hour, point l l2 can move far enough to the left to shiftthe valveA |30 back to"high, or direct drive in the wautomatic unit.

This yields a selective effect of enginebraking andV accelerationavailable tothe car driver within definite' speed ranges of engine andvehicle, wherein neitherengine nor transmission mechanism may be abused,and permits the driver to establish n ilxed reduction ratio for gradientwork where torque rather than fuel economy is desired. It will be notedthat after an excess speed upf shift to high compelled by the governor,when the'settlng is for enforced third drive; the conand the runningresistance of the vehicle. The

adjustments may be 'setso as to require any predetermined throttleopening before downshift octrol mechanism will .resetto third when thegovernor speed falls, and drive in third" will be resumed,'requiring noespecial attention from the curs, and the adjustable stop system Iza-.m.

'enables the service operator to vary the relative car driver.rResumption of lnormal automatic Vshift in fthe 'automatic unit isaccomplished by resetting the handlever 30| in its high. position.

throttle motion upon the shift con- A 291, similarly to the actionVWith-the'handlever' 30| in spinning clutch disc and The motion of thehandlever 30| from low" position to other sector required a lost motionprovision in the linkage of lever 303 to shaft |03, lever |02, andslider |04, so that after jaw clutches 1' and |9 are meshed, the motionof 30| may be continued. Roller 3|2 after completing the stroke ofslider |04 toward mesh of 1 and I9, may ride free of cam face |05 of theslider, so that the lost motion provision is hereinl accounted for. Thisfeature combines the two motions of rocking of |02 and the sliding of|04 on rod |0I.

In Figure 9, manual valve |09 is in the up" position whence pump linepressure from 213 may flow to 212, and thence to brake piston 29| andclutch pistons 19 through the described portings. The valve is shown inthe down position in Figure 10,port 263 from the pump line 213 being cutoff, and line 212 being opened to exhaust passage 260, land regulatingvalve attached at 250' to the casing. Valve 260" is made of springsteel, of a predetermined rate characteristic, such that its exposedarea bears a calculated relationship, for the purpose of controlling thereleased pressure flow, thereby regulating the rates of clutch release,and brake application in the rear unit.

Figure 11 is an enlarged View of the construction of the plunger 323operated by throttle connected lever |22, for manipulating thedifferential valve 320. Abutment member 214 in Figure 9 Works againstspring 91e under thrust from pin of spring 91e in Figure 6. f

The external shell of plunger 323 is bored out internally to t collarwasher 321 which may slide on the adjacent end of the stem 32| of valve320.

` Lock ring 340 prevents the washer 321. from further movement inducedby te'nsion in spring 322.

The first increment of accelerator pedal motion rocks lever |22counterclockwise, further compressing spring 322,. opposing the force ofduid pressure acting on the upper face of valve y 320, resulting in agraduating of the orice between the lower lip'of sleeve 325 and thevalve 320, thereby restricting the pressure ow from space 334 to outlets21S-211 available to create pressure on counter piston 294 in thecylinder space between .abutment or wall 295 in cylinderl warm up theengine, the servo pump gear circulating the transmission caseA oilthrough the described passages.

When it is desired to put the vehicle in motion, the customary clutchpedal, depressed by the foot, separates the mating clutch plates, theoperator shifts the handlever 30| to correspond to neutral to low shiftof plate v|25 of Figure 6. At this point attention is directed to a.valuable adjunct for absorbing the inertia of the main clutch drivenplate and connected parts.` In my construction, the arrangement ofclutch driven shaft 5, gears 1 and I0, and servo pump, and automaticpressure valve 200, provides a predetermined back pressure when drive isremoved from this system by opening of the main clutch.

Spring 20| causes valve 200 to block the flow of the pump, yetpermitting'oil to flow to the transmission bearings. The reactivepressure is here used as a clutch brake to assist the synchronizationrequirements, to give a smooth transition from neutral to low, so thatjaw clutch 1' will reduce quickly to zero speed.

Assuming forward drive synchronized, as soon as the driver relaxes themain clutch pedal, engine torque is delivered to shaft 8, and to theinput annulus gear |2 of the front unit. The car load is assumed to beacting on carrier element 22 connected to shaft 2| which is the outputshaft of the front unit.

vWith load on carrier 22, and engine torque on gear I2, a force isapplied to the sun gear 25 tending to give it a retrograderotatlon.

Brake band 80 of the front unit being normally stressed for locking bythe springs 81, is prevented from slipping and thev retrograde motion isstopped as torque reaction begins.

Gear 25 cannot further rotate, and cage 22 moves in the same directionas the engine conpassage 304' connects to line23l. receiving net Apumpoutput pressure. Y Ported space 335 is joined by lead 210. tocompensator lines 211 and- 211', and is crow-connected to space 333' .bypassage 331'. Spring 322' reacts between the lower-face of valve 320';and the recessed portion of plunger 323', guided by stem 32| of thevalve.

The compensator valve 320' serves the purpo of regulating the rate oftransfer of torque from the geared path of torque to the clutch coupledpath. Itgovems the-degree of loading pressure on the clutch that istaking the drive, at the instant of brake release, as will be apparentfrom this description.

-In'starting,theengine idles atagivenspeed. neutralposition, thedrlvergearingaresep- Theoperatormay 15 nected gear, the planets 24movingorbitally and rotationally, shaft 2| being driven at a ratio to'engine speed, forwardly. v

With springs 91 active to load band 90 of the rear unit for locking, theapplication of engine torque to shaft 2| and load to output shaft 450gives rotation to shaft 50, which then applies torque to the final drivemechanisnr such as road wheels, tractor treads, air or ship prppellersand the like; at low speed ratio, orv reduction in both the front andrear Overrunning torque when the throttle is relaxed, or when the loadis driving the engine as cn downgrades, is overcome by the greatertorque reaction sustaining force of the brake springs, therefore drag isprevented. The application of compensating fluid pressure to subpiston294 lof Figure 6, with the handlever 30| controlling valve |83 throughthe linkage shown, is such that ports 263 `and 204 are connectedwhenever-fthe handlever 30| is placed in the low forward position. Thesub-l piston also serves an additional purpose. l

A similar sub-piston 205' is used to compensate for the action of thefront-unit brake 00,.as,will be described further.

Overrunning Vtorque is then yprevented from shading the' brakes becauseof the excess capacity of springs 91 and 31. The car operator is thenfree from any possibility .of coasting or freewheeling, and my method"increases the factor of positive control under severe operatingconditions, therefore increasing safety. Engine braking in low gear isdesirable from the point of view of maneuverability in trame. since amore accurate control over theslow speed posiward downshift.

always being delivered through brakes I0 and 30 or c1utches`33 and l35;55 and 50.

'I'he driver may now drive at will with low setting of lever 33| andstill obtain the ad vantages of automatic operation. Governor 25|-255through connections 350, 35|, 352 and H may exert an influence on theratio control mechanism of Figure 6. Here the equalizer bar onincreasing governor speeds is. urged to move left and toswingcounterclockwise .about as a fulcrum, 1ever |35 restricting the moveingthe strengths and adjustment of governor springs 252 and 254, spring|25, biasing spring |'4| and toggle spring |98 of Figure 8 and thesetting of the effective lengths of the various rods. ahd leverlinkages. At speeds above car speeds of 8 miles per hour, this settingnormally requires the front unit to re- I main in direct drive, undernormal operating conditions, although the requirements vary fordifferent vehicles, purposes, engine speed and power available, and thelike.

Having considered the automatic operation in y Y one ratio range, theoperation in the second ment.v lAt a givengovernor speed, equivalent toengine-speed, the pivot point ||2 of bar shifts left, lever link ||3shifts right, and the toggle |30 and |39 snaps from left to right bias,causing valve |50 to move to a position to connect ports 236 and 281.This delivers uid pressure from main outlet 233 of the servo pump yandauto matic pressure valve system of Figure i2, to the' head of piston28| in cylinder 282 of the front unit, and Ato passages 218 and 19leading to pistons 12 in cylinders 1| of this unit.`

Piston 28| overcomes the pressure of spring 81, strikes abutment 28Goofrod 280, and disen-A gages brakeu. Pistons 12 load presser-plate 1Iand press the clutch discs 33-36 together, squeezing the clutchdisengaging springs 88.

The transition from low to direct in the front unit has been made, andthe new ratio of drive is the reduction ratio of therear unit only.

For conditions requiring acceleration, maneuvering, or unusual torquedemand, the handlever may be kept in the low position indenitely and themechanism will selectupshift'only in the front unit, depending ongovernor speed means to aiect selection through the linkage 303,355,359, 36d, and 36| of Figure 6, and through lever 132, pin |48, arm|2| and spring |25, which latter forces lever IIB and pin H5 to the mostleftward position allowed by pin IIB bearing against the notch of lever|2 This interaction is so arranged that for normal operation while inlow setting of handlever the movement of pin ||5 to maximum allowed leftposition can force the automatic shift to low within the low speedranges of the gov" ernor only, which is a protection againstunnecessary, long-continued operatin in the extreme low ratio-gearing.

Furthermore, the cam plate |26 so limits counterclockwisemotion of lever|23 about shaft |20, that as soon as the front unit shifts by governoraction to direct drive, the increase in governor speed resulting fromthe opened throttle carries pivot ||2 to the left so far that thepermitted mamum leftward movement of ||5 is not far enough for thedriver, even by full depression of the accelerator pedal 303 to furtherenforce a ldownshii't in the front unit.

Now if severe driving conditions or 11p-grades be met, the governorspeeds may be reduced far enough so that the mechanism will b e ursedto? This speed range "of rcontrol is governor managed up toapproximatelylZ miles per. hour, in which range it is not obedient tooperator willto shift to a higher ratio.V Y

One may determine this speed rangeby varyand throttle pedal position,'the latter providing l `range as noted preceding will now be described.

The car operator in shiftingthe handlever 30| to high position, mayfulll one of the stated objectives, which is to cause'a nearlysimultaneous but actually sequential shift in both the front and rearunits, so as to provide a smooth transition from one intermediate ratioto an adiacent intermediate ratio.

After the arm |23 departs from the cam face of cam plate |25, when thehandlever 30| is put in high position, the lever IIS being urgedcounterclockwise by spring |25 is not further restrained, and for givengovernor 'and throttle settings, mai/'cause the valve |50 to be moved tolow position, approximately at the same time as the valve |68 is shiftedto its hig position. This is true, however, within a limited establishedgovernor range, and at or nearly full throttle pedal position of 303.

At increased governor speeds with relaxed throttle, there is no Aneedfor the mechanical advantage of the extra reduction speed interval of3rd, and this downshift will not occur in the front unit, when thehandlever 30| is moved from low" to high, so that considering overallratios, the operator may skip 3rd speed, and shift .from 2nd to direct;that is, the valve 168 only Full depression of the accelerator pedal303'V when driving at below 59 miles per hour causes the arm ||8 to moveleft using pivot ||2 as a momentary fulcrum, and move link leverr I3left, snapping'togglel |38|39 left, and shifting valve |50 left, closingport 265 and opening ports 263-269 connecting port 261 to the sump. Thisdrains clutch cylinders 1|, line 218, cylinder 282 and line 214; springs81 applying brake 80 to drum 28; eventually stopping the rotation of thedrum, and sungear 25 which serves as the reaction element for thegearing of the front unit.

stop |23.

' per hour point,

establishing thereupon the reduction drive.

At all governor the pivot point ||2 is moved too far left for the 'pin||5 to further enforce a downshift, since lever ||6 is receiving themaximum eiort deliverable by spring |25; the lever system 12| and HEbeing prevented from further clockwise Yrotation by When the speeddrifts below the given 59 miles the 'ability of pin ||5 to enforce adownshift is resumed, as will be understood lfrom the foregoingdescription.

descending governor the effect of the throttle speeds above 59 miles perhour,

aaoatis Ils end notch tu, limiting the leftward-peintn severe up-gradeswhich impose a heavy torque` on the engine, registered as a decrease .ingovernor speed, and with open throttle recording the operators torquedemand, the downshi'ft will occur within afdeflnite speed range suchthat smooth transition from direct Ito reduction in the front unitoccurs, and such that the available torque is in general proportional tothe torque demand. On levell roads. the relative points of pivots ||2and ||5 as mutually acting fulcra will therefore determine a differentresponse charac- 4teristic by the engine's power to sustain a givenspeed for the existin'g load, conditioned by the accelerator pedalposition. On downgrades, with relaxed throttle, the governor actioncauses the wherethe governor forces might exert an influence forupshift; When the handlever 30| is placed in the neutral position, thegear i9y and front unit to go to direct drive and remain. there over alldriving speed ranges above a predeter-` mined and selected point ofapproximately 17 miles perho'ur. In the range vof 17459 miles an houritis possible for the car driver. to establish a downshift throughacceleration demand set up 't shaft |35. .Lever 420 is arranged tointersect lever 4|1 pivotedon pin 4H!` of cam plate |26, so

that for governor speeds in excess of a predetermined speed, forexample, 40 miles per hour, a shift of handlever to low will not movevalve |68, but compressspring. 4|6 through lever 4|5.

While the handiever itself mav be moved. the resistance of spring M6 lisfeit against the hand,

and the lever 4|5 will move clockwise, stressingA that spring withoutmoving the valve |68, or the cam plate |26.

The reaction-of lgovernor springs 252 and 254 in the system comprisingsleeve 255, collar 251, arm 350, shaft arm 352, rod ||0,and notch oflever provides a yieldable system between teeth I9' slide to-anon-driving point, and valve |66 movesto direct drive p'osition for therear unit.'

, Upon shifting to reverse` themain clutch pedal 'is depressed, applyingthereactive iiuid pressureload of the pump and lubrication systemv aspreviously described, to absorb the inertias of the rotatingparts, andgear I9 ismoved along helical vsplines 6 from right Pto left as inFigure l'.

The slider |04 through cam 3|2 on arm |02 `traverses along r'od' 0|fixed to the casing, and

theearm |00 moves gear 'I6 from right to left into mesh with idler gear6. Infshiiting from `reverse' 'to neutral, the sliding gear I9 isdemeshed from For ordinary passenger car work it is v-desired that drivein reverse shall be at only'one reduction speed, whereas in variousdraft gear, logging engines, military tanks, excavators and the like itmay be useful to arrange the transmission and controls so that thesamerange of variable speed 'ratios are available in forward and reversedrive,

. while the present application relates particularly to passengervehicles in theexamples. Therefore Ishowmeans to prevent the automaticshift from taking place ywhen theI handlever 30| is put in reversa anddrive can.on1y-be in reverse at low ratios in both units.

When cam plate |26 is in reverse position,

hook |56, oiFig. '7l swings to prevent arm |30 of weights 25|, andthe-control parts moved by acy celerator pedal 303 and handievei` 30|.Any governor force transmitted back through the control linkage to theaccelerator pedal 303', must passr f through spring |25, therefore theoperator can ent compression force of'the spring.,

` only feel that forceup to the limit of the inhere' The travel oiiever|32 of Figure 7 with respect to lever |23 from idling enginethrottleposition to the point where pin ||6 begins t'o cause |2| to rockprovides a range of exclusive Aengine throttle control for pedal 303which maybe adjusted to the power requirements, and guarantees suicienttorque development `before the automatic control interaction can beinitiated. Beyond this point,

the range of pedal movement is always involved Fig. 8 and pivotl |45vfrom'moving-to the right, preventing valve |50 from being m'ovedl tothe 'right to direct drivepcsitien fer the 'front unit.

The governor and throttle -linkagefcannot now operate toggle |36|39 withvalve |50 locked in 1ow position. As soon as the handlever is moved fromreverse, hook`|56 no longer restrains a'rm |39.-

. Ifv an eutcmatic'etic increase ic'dsii-,ed fer.

reverse, finger 56 may be' mittedand at a given governor speed, thefront unit will change from low vto direct drive. cam plate |26 throughslot |55 guides pin |59 of lever |51 torock lever-|60and valve |68 toits limit of clockwise travel, lifting valve |66 so that servo pressure.from line 238v through port 263 cannot iilow to port 262, so that thesprings are active to lock brake -80 of the rearunit. The claims hereinare directed to subject matter embodied'in the division of-artgwhiehincludes operation and` control of clutches as distinctfrom myvabove-noted parent application now matured as U. S. 2,193,524, whichwas directed to subject matter pertaining to transmission controls.

The scope oi' my linvention isbelieved to be Ybroader than the specicexamples of application with change of ratio vexceptfor the described lchecks and stops.

The driver may shift the cam plate4 |26 from "high to low .position atany time, except -when the governor is at high speed positions as rnoted above. When this is done, valve |66 ofthe rear unit is moved downas in Fig-ured, connect- 'ing ports 263 and 264, and venting port 26|,line 21,2, cylinder 262, Alin'e 216, and cylinders 15 of the rear unit.When the pedal is depressed. the lever |3| is-rotatd until pi'n ||6forces'arm |2| to move counterclockwise against spring |25,.causing pin|15 to take a position toward the left as in ,Figure 7', establishing a'coupled relationship betweenpin described herein, since many of thedetails may Abe modiiled in many ways within the skill of one versed inthe art.

The utility of my invention is in no way circumJ scribed to thedemonstration herewith given, i. e.,

@an automobile power control device, but its apei plicability toexcavators, mists-tractors and sim- -ilar machines, machine tool drive,vpower shafting of boats, rail cars, -andaeronautical vehicles isexpresslystated herewith. ,The scope oi ny in ihgthe statements oi'vention will be apparent the appended claims.

I claim: L i

1. In automatic controls lfor drivingf mecha-` During lreversel shift,the

